Various fluid such as fuel and lubricating oil are indispensable in operating the engine. Let's take a look at the characteristics of these oils in order.
Characteristics of gasoline
Octane number
The octane number is one value displaying the characteristics of gasoline, which is a numerical representation of its anti-knock properties.
The higher the number, the less likely knocking is to occur. Knocking is when the gasoline combusts abnormally in the cylinder, making a continuous sound as though a hammer were hitting the cylinder wall, lowering the engine output.
In worst case scenarios, the valve, piston, spark plug and more can be damaged. The octane number of gasoline generally sold does not differ greatly, with regular gasoline at about 90 and premium gasoline (unleaded high octane) at about 100, regardless of manufacturer.
Engine oil
The engine oil lubricates each part of the engine. There are various types of engine oil based on the engine characteristics and usage conditions, so it is necessary to check the appropriate oil to use.
The engine oil lubricates each part inside the engine. It also has various other important functions and properties.
Lubricating effect
Friction occurs on sliding surfaces, but it can be minimized if there is something that reduces friction on both surfaces. Lubricating oil makes an oil film on each sliding part inside the engine, lubricating and reducing friction between the sliding parts.
Cooling effect
There is a cooling system installed in the engine, but it is difficult for the cooling system to cool the pistons and sliding sections, and so when the lubricating oil circulates it takes away ambient heat and cools these areas.
Cleaning dispersion effect
Sludge and metallic dust are generated inside the engine due to combustion. If these accumulate in the sliding parts and oil passages, wear increases, oil passages become blocked, and lubrication failure occurs.
Lubricating oil therefore keeps these in the oil without depositing them in the engine.
Sealing effect
There is a gap between the piston and the cylinder which is sealed by a piston ring, but it can not be sealed completely.
Lubricating oil creates an oil film that improves the seal between the piston and cylinder, reducing the gas escaping through the gap.
Engine oil also has the following roles.
Anti corrosion effect
Makes it difficult for the oil film to be broken (anti-corrosion additives which act like a coating agent, tightly binding to iron, are added)
Oxidization neutralizing effect
Highly corrosive, acidic gases generated by combustion enter the oil and so the oil acts to neutralize this acid to protect metal parts from corrosion and wear.
Improved oxidation stability
Oil is oxidized as air enters it due to the heat from explosions, friction and churning.
Generally, the oxidation rate speeds up as the oil temperature increases, and so oxidation stability is improved by adding antioxidants.
(When oil becomes oxidized, oxidization degradation matter is formed, which spoil the oil's lubricative and clean dispersiveness properties)